Battery-powered devices (e.g., consumer electronic devices, electric and hybrid automobiles, etc.) are charged from a power source (e.g., AC power outlet) through a charging device. The charging device couples the battery to the power source through an adaptor. The cord extending between the power source and the battery-powered device can take up space. In situations where multiple devices require charging, each with their own charger and cord, the charging area can become cramped and inconvenient.
Approaches are being developed that use over-the-air or wireless power transmission between a transmitter and a receiver coupled to the electronic device. Wireless power transmission using inductive coils is one method considered as an un-tethered method for transferring power wirelessly through a coupled wireless power signal. In wireless power transmission, power is transferred by transmitting a wireless power signal through a transmit coil. On the receiver side, a receive coil may couple with the transmit coil through the wireless power signal, thus, receiving the transmitted power wirelessly. The distance between the transmitter coil and receive coil, at which efficient power transfer can take place, is a function of the transmitted energy, the distance, and the alignment of the power transfer coils. The coupling coefficient (k) is a function of the distance and alignment between the coils, the coil sizes, and materials. The power conversion efficiency (e.g., coupling factor, coupling quality) may be significantly improved if the coils are sized and operated at such a frequency that they are physically within the so-called “near-field zone” of each other.
Conventional wireless power charging systems may have an interface that informs the user of the status of the wireless power transfer system. The interface is electrically coupled via a wired connection with the power supply of the wireless power transmitter. The status indicator is typically an LED that flashes in some pattern corresponding to a particular status. The inventor has appreciated that in some situations, the status indicator may be difficult to locate for the user to see—particularly when integrating within objects that are difficult to run the required wires or that are optically opaque. As a result, conventional solutions have resulted in a disruption of an otherwise contiguous object, in status indicators being placed in locations that are inconvenient for the user to see and/or are obstructed by the receiving device being charged, among other issues.